Effects of Total Solar Eclipse on Ionospheric Total Electron Content over Antarctica on 2021 December 4

Idosa, Chali; Rikitu, Kebede Shogile

doi:10.3847/1538-4357/ac6c89

Cited by 12 publications

(4 citation statements)

References 20 publications

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“…PSE2018 and PSE2022 had similar ionospheric behaviors under the lunar shadow with clear TEC decreases (<−40%) that moved from Antarctica to South America (see Figures 4 and 5). Despite the fact that the maximum obscuration in both eclipses is around 60% at 350 km altitude, the DVTEC values we obtained were consistent with the values presented for the total solar eclipses over South America [6,10,11,13,27,31,43,45,46,48] and Antarctica [49]. Also, τ values were between 1 and 45 min, and the ionospheric effects caused by PSE2018 and PSE2022 persisted after 24 UT because the concentration of electrons does not return to normal levels (see Figure 6 and Table 1).…”

Section: Ionospheric Tec Behaviorsupporting

confidence: 88%

“…The zone of the penumbral eclipse covered Antarctica and was observed over small southernmost sections of southern South America, Africa, New Zealand, and Australia between 5.48 UT and 9.62 UT. Idosa and Rikitu [49] studied TEC effects due to TSE2021 at six GPS stations in Antarctica. Over the six stations, the TEC value decreased during the eclipse.…”

Section: Introductionmentioning

confidence: 99%

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IonosphericTotal Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

Valdés-Abreu,

Díaz,

Bravo

et al. 2023

Remote Sensing

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This is one of the first papers to study the ionospheric effects of two solar eclipses that occurred in South America and Antarctica under geomagnetic activity in different seasons (summer and autumn) and their impact on the equatorial ionization anomaly (EIA). The changes in total electron content (TEC) during the 15 February 2018 and 30 April 2022 partial solar eclipses will be analyzed. The study is based on more than 390 GPS stations, Swarm-A, and DMSP F18 satellite measurements, such as TEC, electron density, and electron temperature. The ionospheric behaviors over the two-fifth days on both sides of each eclipse were used as a reference for estimating TEC changes. Regional TEC maps were created for the analysis. Background TEC levels were significantly higher during the 2022 eclipse than during the 2018 eclipse because ionospheric levels depend on solar index parameters. On the days of the 2018 and 2022 eclipses, the ionospheric enhancement was noticeable due to levels of geomagnetic activity. Although geomagnetic forcing impacted the ionosphere, both eclipses had evident depletions under the penumbra, wherein differential vertical TEC (DVTEC) reached values <−40%. The duration of the ionospheric effects persisted after 24 UT. Also, while a noticeable TEC depletion (DVTEC ∼−50%) of the southern EIA crest was observed during the 2018 eclipse (hemisphere summer), an evident TEC enhancement (DVTEC > 30%) at the same crest was seen during the eclipse of 2022 (hemisphere autumn). Swarm-A and DMSP F18 satellite measurements and analysis of other solar eclipses in the sector under quiet conditions supported the ionospheric behavior.

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Section: Ionospheric Tec Behaviorsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

IonosphericTotal Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

Valdés-Abreu,

Díaz,

Bravo

et al. 2023

Remote Sensing

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“…It is noted that while deviations on the order of 40 TEC units may seem quite large, line of sight measurements at low elevation angles are sensing a much larger portion of the ionospheric layers than the more common vertical TEC measurements. Idosa and Rikitu (2022) show similar modification of TEC upwards of 14 TEC units under the region of shadow for the same event. One question about the observations from PG4/5 remains outstanding: Why is there a step‐function‐like increase in TEC immediately after the global peak obscuration, specifically in PRN 8 and 30 but not otherwise?…”

Section: Discussionmentioning

confidence: 74%

The 2021 Antarctic Total Eclipse: Ground Magnetometer and GNSS Wave Observations From the 40 Degree Magnetic Meridian

et al. 2023

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Solar eclipses provide an opportunity to study ionospheric dynamics in a way unlike any other. The majority of the sun's direct energy link into Earth's atmosphere is rapidly turned off and on again, and the impact of such a modulation is profound. Anyone who has experienced an eclipse from under the track of totality in person can attest to the dramatic temperature swings that occur from the momentary absence of sunlight. From the perspective of the global atmospheric system, the effects are equally noteworthy. Not only does an eclipse directly affect the thermosphere (Li et al., 2021;McInerney et al., 2018), but the obscuration related reduction in photoioniza tion undoubtedly impacts the ionospheric composition (and therefore dynamics) as well (X. Chen et al., 2021;Dang et al., 2018). As a result of changes to the ionosphere's local total electron content (TEC), currents flowing within the ionosphere should also be modified by an eclipse. However, the exact physical description of how these currents are modified is an unsettled question, particularly in polar regions where data coverage is sparse and eclipses are relatively rare. It is therefore necessary for multi-point observations supported by modeling efforts to advance our understanding of eclipse related effects.Several studies have suggested that ionosphere-thermosphere (IT) dynamics will be altered during an eclipse. One of the main drivers of these modified dynamics (at least at mid to low latitudes) is expected to be changes in the neutral wind structure that create counteracting flows in opposition to the regular wind dynamo (Aa et al., 2020;Choudhary et al., 2011;St.-Maurice et al., 2011). Because of coupling between the ionosphere and thermosphere, the normal evolution of the ionospheric electrojets are likely to be impacted as well by deviations in neutral

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“…The responses of ionospheric TEC indicate both the positive and negative ionospheric effects as a result of space weather alerts such as solar flares, coronal mass ejections, and geomagnetic storms. The ionospheric TEC, on the other hand, exhibits a negative ionospheric response during the solar eclipse because the eclipse reduces the degree of ionization [25]. It is currently unknown how ionospheric TEC behaves during the formation of sun halo days.…”

Section: Introductionmentioning

confidence: 99%

Responses of Total Electron Content to Solar Flares over Low and Mid-Latitude Regions during Sun Halo Day

Idosa,

Adhikari,

Shogile

2023

J. Nep. Phys. Soc.

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The responses of total electron content (TEC) to solar flares over low- and mid-latitude regions during the sun halo days were investigated. The research is based on GPS data obtained from Bangalore (13.02117°N, 77.57038°E) on May 24, 2021; Cape Town (-33.918861°N, 18.423300°E) on October 26, 2020; and North Dakota (46.55756°N, -96.472300°E) on December 27, 2021, during the solar halo days. The results of this study demonstrate that the values of TEC increased at Bangalore and Cape Town stations during solar halo days as compared to other days. However, over the North Dakota station, TEC during the sun halo day was greater than that on the days before and after the halo day from around 19:00 UT to 23:59 UT hours. During the sun halo over Bangalore and Cape Town stations, positive relative changes in TEC prevail, suggesting that the action of the interplanetary electric field, the prompt penetration electric field, and the disturbance dynamo electric field lead to higher TEC values. However, during the sun halo over North Dakota station, negative relative changes in TEC prevail, which might be related to the consequence that low solar activity with no earth’s field disturbances (a positive Dst) leads to lower ionospheric TEC values. Stations that have greater relative changes in TEC have shown greater power spectrum and global wave spectrum energy. Cape Town has a greater relative change in TEC, a greater power spectrum, and a larger global wave spectrum than Bangalore and North Dakota stations. The values of TEC over three stations are different due to the latitudinal and longitudinal differences in addition to the universal time effects. Finally, solar flares have a major influence on ionosphere electrodynamics, and the upward drift velocity of ionospheres at the low latitude station is more strongly influenced by solar flares due to the effects of the ExB drifts, which induce TEC disturbances during the halo days over the suggested stations.

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Effects of Total Solar Eclipse on Ionospheric Total Electron Content over Antarctica on 2021 December 4

Cited by 12 publications

References 20 publications

IonosphericTotal Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

IonosphericTotal Electron Content Changes during the 15 February 2018 and 30 April 2022 Solar Eclipses over South America and Antarctica

The 2021 Antarctic Total Eclipse: Ground Magnetometer and GNSS Wave Observations From the 40 Degree Magnetic Meridian

Responses of Total Electron Content to Solar Flares over Low and Mid-Latitude Regions during Sun Halo Day

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